check that a password meets all the requirements

validatePassword.java

/*
 * validatePassword: check that a password meets all the requirements
 * @param    passwd: a string with the password that you want to check
 * @return     true: meet the requirements
 * @return    false: doesn't meet the requirements
 */
public static boolean validatePassword(String passwd) {
	boolean valid = false;
	Pattern pattern = Pattern.compile("(?=.*[0-9])(?=.*[a-z])(?=.*[A-Z])(?=.*[~`!@#$%^&*()+=\\-\\[\\]:.;,<>?/'\"{}|_])(?=\\S+$).{8,12}");
	if (passwd != null) {
		Matcher mather = pattern.matcher(passwd);
		if (mather.find())
			valid = true;
	}
	return valid;
}
/*  - - NOTES - -
 * (?=.*[0-9]) a digit must occur at least once
 * (?=.*[a-z]) a lower case letter must occur at least once
 * (?=.*[A-Z]) an upper case letter must occur at least once
 * (?=.*[~`!@#$%^&*()+=\\-\\[\\]:.;,<>?/'\"{}|_]) a special character must occur at least once
 * (?=\\S+$) no whitespace allowed in the entire string
 * .{8,12} at least 8 chars and 12 max
 */